Lifting-jack.



PATENTED MAY 10, 1904.

G. DERKSEN. \LIFTING JACK.

APPLIOATION FILED SEPT. 19, 1903.

N0 MODEL.

lINiTED STATES Patented May 10, 1904.

(iERI-IARI) DERKSEN, OF ST. MARTINS, IVISCONSIN.

LlFTlNG-JACK.

SPECIFICATION forming part of Letters Patent N0. 759,248, dated May 10, 1904.

Application filed September 19, 1903. $erial No. 173,869. (No model.)

To all whom it may concern.-

Be it known that I, GERHARD DERKSEN, a citizen of the United States, residing at St. M artins, 1n the county of l\ililwaukee and State of \Visconsm, have invented a new and. useful Lifting-Jack, of which the following is a specification.

This invention relates generally to liftingjacks, and more particularly to that class thereof in which the lifting-bar is provided with a ratchet which is alternately engaged by lifting and lockingpawls, said pawlsbeing operated by means of a lever mounted in a suitable frame, which also carries the liftingbar; and the object of the invention is to providea strong, durable, and efficient construction of lifting-jack of this kind; and with these objects in view the invention consists in the novel features of construction and combination, all of which will be fully described hereinafter and pointed out in the claims.

In the drawings forming a part of this specification, Figure 1 is a perspective view .of the lifting-jack constructed in accordance with my invention. Fig. 2 is a sectional elevation showing the lifting-bar as moving upwardly. Fig. 3 is a similar view showing the lifting-bar locked,ready to be moved upwardly by the movement of the lifting pawl and lever. Fig. 4c is a transverse sectional view on the line 4 4C of Fig. 2, and Fig. 5 is a horizontal sectional view on the line 5 5 of Fig. 2.

In carrying out my invention I employ a support or frame A, a lifting-bar B, movable vertically therein through the medium of a lever G, lifting-pawl D, and locking-pawl E, in a manner hereinafter fullyexplained. In constructing the frame or support I employa base A, upon which rests the parallel standards A, said standards being securely fastened to the parallel lugs A and an integral web A- braces the said standards at their lower end. The inner faces of the standards A are provided with vertical guiding-ribs A, which Work in the grooves B, produced in the opposite sides of the lifting-bar B, and for the greater portion of itslength this bar is slotted transversely and vertically, as shown at B a cross-pin B which connects the upper ends of the standards, working in said slot and serving to guide the upper portion of the liftingbar during its vertical movement. The rear face of the lifting-bar isprovided with a series of ratchet-teeth B which are adapted to be engaged by the lifting and locking pawls heretofore referred to, and the forward side is provided with forwardlyprojecting arms 13, which are adapted to be placed beneath the article to be raised.

The lever G has a cam-shaped head 0, provided with trunnions which are journaled in the parallel standards A, and opposite the cam C is a bifurcated foot 0. The camhead C is intended to operate upon the lifting-pawl D. while the bifurcated foot C is intended to operate upon the locking-pawl E. The lifting-pawl I) is arranged between the parallel standards upon a shaft D, carrying a roller D said roller being mounted upon the said shaft in the bifurcated end D of the pawl, the ends of the shaft 1) being flattened, as shown at D, and adapted to play vertically in the vertically-elongated slots A, produced in the standards adjacent their upper ends, the said roller being adapted to en gage the cam-head C of the lever, and upon the downstroke of the lever the head raises the roller, and consequently the pawl, and the nose D of the pawl being in engagement with the ratchet-face of the lifting-bar said bar will be lifted vertically during the downstroke of the lever. During these movements the locking-pawl E is held in engagement with the ratchet-face of the lifting-bar by means of a spring E, fastened to one of the standards and bearing against the rear side of the pawl,

'it being understood, of course, that the pawl is provided with integral or separate pivotal bearings, which are journaled in the parallel standards. This pawl is provided with an upwardly and rearwardl y extending arm E, carrying a spring-finger E which is adapted to be engaged by the bifurcated foot O. carried by the lever, so that upon the downstroke of the lever the foot will engage the springfinger and cause the pawl E to be held in engagement with the lifting-bar; but upon the reverse movement of thelever the bifurcated foot rides over the spring-finger, and although the locking-pawl may be momentarily disengaged from the lifting-bar, as shown in Fig. 2, the lifting-pawl is still in engagement with the said lifting-bar, and at the limit of its upward movement and the moment the bifurcated foot passes beyond the spring-finger the spring E will throw the locking-pawl back into engagement with the ratchet-face of the lifting-bar.

As the lever is moved upwardly the pawl and its roller and shaft will drop by gravity, and the upper side of the lever is recessed, as shown at 0*, for the purpose of receiving the roller of the pawl when the lever is thrown upwardly to its extreme limit, thereby permitting the pawl to drop the full limit of the slot A. The pawl is formed with a depending extension D and the lever is provided with an upwardly-extending lug or extension which is adapted to ride under the exten sion D when the lever is thrown upwardly to its limit and which serves to throw the pawl D positively into engagement with the lifting-bar upon the commencement of the downstroke of the lever, as the lug C passing back under the extension D, will throw the nose D into engagement with the ratchetface of the lifting-bar. Thus it will be seen that the nose being in engagement the continued downward movement of the lever will cause the cam-head G to lift the roller, and consequently the pawl, and force the lifting-bar upwardly. These operations are repeated until the article to be raised has been lifted the desired extent.

The lifting-pawl D is provided with an upwardly-extending finger D by means of which the said pawl can be drawn out of engagement with the lifting-bar, and the lockingpawl E is formed with a laterally-extending finger E projecting through an opening A formed in the adjacent standard,and by means of which finger the locking-pawl can be thrown out of engagement with the lifting-bar when desired.

Having thus fully described my invention, what 1 claim as new, and desire to secure by Letters Patent, is

1. A lifting-jack comprising a frame, a ratchet-faced lifting-bar, a vertically-movable liftingpawl, a pivoted spring-actuated locking-pawl, and a lever having a head adapted to engage the lifting-pawl, and a foot, adapted to engage the locking-pawl, as set forth.

2. A lifting-jack comprising a frame, a ratchet-faced lifting-bar, a vertically-movable lifting-pawl, a pivoted spring-actuated locking-pawl carryinga spring-finger and a lever having a cam-head adapted to move the lifting-pawl and a bifucated foot, adapted to engage the spring-finger of the locking-pawl, as set forth.

3. A lifting-jack comprising a frame, a ratchet-faced lifting-bar sliding therein, a vertically-movable lifting-pawl, having a downwardly-extending portion, a lever having a cam-head, and an upwardly-extending portion adapted to engage the downwardly-extending portion of the pawl, and a lockingpawl adapted to engage the lifting-bar, as set forth.

4. A lifting-jack comprising a frame, a lifting-bar having a ratchet-face, a liftingpawl having a bifurcated lower end, and a roller journaled in said bifurcated end, a lever having a cam-head, and a bifurcated foot, and the spring-actuated locking-pawl, having a rearwardly-extending arm provided with a spring-finger, substantially-as described.

5. In a lifting-jack the combination with a frame comprising a base and parallel standards constructed and arranged as described, of the lifting-bar sliding in the frame, and having a ratchet-face, a lifting-pawl mounted upon a vertically-movable shaft, and carrying a roller in its bifurcated lower end, said pawl being provided with a depending extension, a lever having a cam-head, an upward extension, a recess at the rear of the cam-head,

and a bifurcated foot, arranged substantially opposite the cam-head, and a locking-pawl, pivoted in the frame, and having a rearwardlyextending arm provided with a spring-finger, all of said parts being arranged and adapted to operate substantially as specified.

GERHARD DERKSEN. WVitnesses:

LOUISA BRUNN, MAY EUsLIN 

